But if you say so, it will usually be clearly pointed out, for example, pouring out the remaining 23% for the second time.

Only 23% is poured out for the second time, so we usually unify "1" as the percentage of the original quantity.

This is also to avoid ambiguity. Some students think that it is the original quantity, while others think that it refers to the first pour, each has its own reasons, and it is difficult to say clearly.

But in most cases, it refers to the original work (unless the title clearly indicates, of course, the former shall prevail)

To make a long story short, do more and you will understand. Most teachers will tell you.